Mixer for a melt spinning apparatus

ABSTRACT

A modification of a spinning pump wear plate that enables it to be used as a means to distribute polymer to spinning packs and as a mixing device directly upstream of the spinning pump. The inlet passage is formed of a plurality of channels through opposite sides of the wear plate with each channel containing a plurality of stationary mixing elements. Caps enclose the opposite sides and provide the means to connect successive channels to form a continuous folded enclosed inlet passage connecting the polymer source and the spinning pump.

- United States/Patent [1 1 Bydal Mar. 26, 1974 [54] MIXER FOR A MELT SPINNING FOREIGN PATENTS OR APPLICATIONS APPARATUS 970,285 9/1964 Great Britain [75] Inventor: Bruce A. Bydal, Martinsville, Va.

[73] Assignee: E. I. du Pont de Nemours and Primary Examinerpeter Feldman C0mpany,'wilmington Assistant Examiner-Alan Cantor [22] Filed: Mar. 2, 1972 [57] ABSTRACT [21] Appl. No.: 231,170 I A modification of a spmmng pump wear plate that enables it to be used as .a means to distribute polymer to [52] US. Cl 259/4, 137/573, 137/576 Spinning packs and as a mixing device directly [51] Int. Cl B01f5/00 Stream f h i i p. The inlet passage is [58] Field of Search 259/4; 425/3822, 200, formed of a plurality of Channels through Opposite 425/205; 137/571 576 sides of the wear plate with each channel containing a plurality of stationary mixing elements. Caps enclose [56] References Cited the opposite sides and provide the means to connect 1 UNITED STATES PATENTS successive channels to form a continuous folded en- 3.701.619 10/1972 Appeldoorn et a1 259/4 x Closed inlet Passage Connecting the P y Source 3,664,638 5/1972 Grout et a1. 259 4 an he spinning pump. 3,704,006 11/1972 Grout et a1. 259/4 3577308 1 Claim, 2 Drawing Figures 5/1971 Van Drunen et a1. 259/4 X MIXER FOR A MELT SPINNING APPARATUS BACKGROUND OF THE INVENTION This invention is concerned with the manufacture of Synthetic fibers and, more particularly, with mixing polymer directly upstream of a meter pump supplying with respect to dispersion of additives. Mixing devices for fluid streams, and particularly viscous fluids such as molten polymers or polymer solutions, are known which require no moving parts. These and other similar devices contain a plurality of stationary mixing elements arranged in series which cause mixing by various combinations of division, displacement and recombination of fluid streams passing through.

When a large number of mixing elements is required to achieve the desired degree of mixing, this can result in a rather long arrangement which may not be compatible with the required location of such a mixer,

It is known to use a wear plate or an adapter plate for mounting spinning pumps on a spinning machine block.

One method of construction of such wear plates is described'by Bayer et al. in U. S. Pat. No. 3,050,846. The present invention involves a modification of a spinning pump wear plate that enables it to function as a means to distribute polymer to spinning units and as a compact mixing device of simple construction.

SUMMARY OF THE INVENTION A melt spinning apparatus that includes a source of molten polymer connected to a wear plate having opposed sides and through which polymer is distributed from the source to a plurality of spinning packs by means of a pump connected to inlet and outlet passages in the wear plate is modified to include a mixing device. The device involves the inlet passage being comprised of a plurality of straight, hollow channels passing through the wear plate from one to the other of said opposed sides; a plurality of stationary mixing elements positioned in each of said channels forming spaced groups of elements; and a pair of caps enclosing said opposed sides, each of said caps in combination with said opposed sides forming at least oneside channel, each of said side channels being connected with two of said straight channels, the combination of straight and side channels providing a continuous enclosed, folded inlet passage connecting said source and said pump.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a partial schematic, perspective drawing of a spinning position utilizing the invention.

FIG. 2 is a plan view partially broken away, of a spinning pump wear plate modified according to the invention.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENT In the drawing, molten polymer l0 from a source (not shown) is passed through a heated transfer line elbow 12, to a spinning position to block 16 where it enters the spinning pump wear plate 20 through inlet passage 22 connected to spinning pump 24 which is a gear pump of the general type described by Heckert in U. S. Pat. No. 2,281,767. From the pump 24, the polymer exits through outlet 25 into multiple paths 26 to several different spinning units (not shown) housed in block 16. An additive may be injected into the polymer at location 14 in elbow 12 or directly into the mixer entrance 22 for subsequent mixing. The spinning units housed in spinning block 16 are conventional filterpack and-spinneret asemblies from which filaments are extruded. The wear plate 20 is modified to serve as a mixing device by arranging the inlet passage 22 to form a continuous folded enclosed passage with a plurality of stationary mixing elements 30 in each folded section of the passage.

In the embodiment of FIG. 2, wear plate 20 has a plurality of straight, hollow channels 32, 34, 36 passing through it from one side 21 to the other side 23. A pair of caps 27, 29 have channels grooved into their inner surface and are attached to the sides 21, 23 of wear plate 20 to connect the straight channels and form a continuous folded passage. More particularly, channel 31 in cap 29 connects straight channels 32, 34 at one end while channel 35 in cap 29 connects passages 34, 36 and similarly channel 33 in cap 29 connects straight channel 36 with channel 38 leading to the inlet of pump 24. In the preferred embodiment, the channels are found in cross section to accommodate curved elements 30 which extend to the channel walls and divide it into two separate paths. While only two elements 30 are illustrated in each channel, the number of elements installed in each channel and the number of channels and their length depends on the degree of mixing desired. The elements are in spaced groups (i.e., each group separated by at least the length of the channels in the caps 27, 29) and perform as well as a single continuous formation of elements disclosed by the prior art. While preferably round, the channels may be of any cross-section dependent upon the type of mixing elements to be installed, e.g., square or round, and may have internal keyways to properly index elements which require it. The number of channels and length thereof is selected dependent upon the number of mixing elements required to achieve the desired degree of mixing.

This apparatus is particularly suitable for mixer installations where conditions do not permit installation of a single, long, continuous, stationary mixing device. By this folded channel arrangement, a large number of mixing elements can be installed in a process stream or a transfer line in a space of only a few inches. The end caps 27, 29 provide ready access to the elements 30 for changing repositioning and general overall ease of maintenance.

What is claimed is:

1. In a melt spinning apparatus that includes a source of molten polymer connected to a wear plate having opposed sides through which polymer is distributed from the source to a plurality of spinning packs by means of a pump connected to inlet and outlet passages in the wear plate, the improvement comprising said inlet passage being comprised of a plurality of straight, hollow channels passing through the wear plate from one to the other of said opposed sides; a plurality of stationary mixing elements positioned in each of said 3 4 channels forming spaced groups of elements; and a pair tion of straight and side channels providing a continuof caps enclosing said opposed sides, each of said caps ous enclosed folded inlet passage connecting Said in combination with said opposed sides forming at least one side channel, each of said side channels being connected with two of said straight channels, the combina- 5 source and said pump. 

1. In a melt spinning apparatus that includes a source of molten polymer connected to a wear plate having opposed sides through which polymer is distributed from the source to a plurality of spinning packs by means of a pump connected to inlet and outlet passages in the wear plate, the improvement comprising said inlet passage being comprised of a plurality of straight, hollow channels passing through the wear plate from one to the other of said opposed sides; a plurality of stationary mixing elements positioned in each of said channels forming spaced groups of elements; and a pair of caps enclosing said opposed sides, each of said caps in combination with said opposed sides forming at least one side channel, each of said side channels being connected with two of said straight channels, the combination of straight and side channels providing a continuous enclosed folded Inlet passage connecting said source and said pump. 